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PHI elimination shouldn't require machineloopinfo since it's used at -O0. Move the requirement to LiveIntervalAnalysis instead. Note this does not change the number of times machineloopinfo is computed.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111285 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2010-08-17 21:00:37 +00:00
parent 6542416560
commit 148341cc9b
3 changed files with 13 additions and 11 deletions
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5
lib/CodeGen/LiveIntervalAnalysis.cpp
View File

@ -62,9 +62,10 @@ void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
AU.addRequired<AliasAnalysis>();
AU.addPreserved<AliasAnalysis>();
AU.addPreserved<LiveVariables>();
AU.addRequired<LiveVariables>();
AU.addPreservedID(MachineLoopInfoID);
AU.addPreserved<LiveVariables>();
AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineLoopInfo>();
AU.addPreservedID(MachineDominatorsID);
if (!StrongPHIElim) {

16
lib/CodeGen/PHIElimination.cpp
View File

@ -45,22 +45,22 @@ char &llvm::PHIEliminationID = PHIElimination::ID;
void llvm::PHIElimination::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreserved<LiveVariables>();
AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineDominatorTree>();
AU.addPreservedID(MachineLoopInfoID);
AU.addPreserved<MachineLoopInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool llvm::PHIElimination::runOnMachineFunction(MachineFunction &MF) {
MRI = &MF.getRegInfo();
MLI = getAnalysisIfAvailable<MachineLoopInfo>();
bool Changed = false;
// Split critical edges to help the coalescer
if (LiveVariables *LV = getAnalysisIfAvailable<LiveVariables>())
if (LiveVariables *LV = getAnalysisIfAvailable<LiveVariables>()) {
MachineLoopInfo *MLI = getAnalysisIfAvailable<MachineLoopInfo>();
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)
Changed |= SplitPHIEdges(MF, *I, *LV);
Changed |= SplitPHIEdges(MF, *I, *LV, MLI);
}
// Populate VRegPHIUseCount
analyzePHINodes(MF);
@ -380,7 +380,8 @@ void llvm::PHIElimination::analyzePHINodes(const MachineFunction& MF) {
bool llvm::PHIElimination::SplitPHIEdges(MachineFunction &MF,
MachineBasicBlock &MBB,
LiveVariables &LV) {
LiveVariables &LV,
MachineLoopInfo *MLI) {
if (MBB.empty() || !MBB.front().isPHI() || MBB.isLandingPad())
return false; // Quick exit for basic blocks without PHIs.
@ -397,7 +398,8 @@ bool llvm::PHIElimination::SplitPHIEdges(MachineFunction &MF,
// out-of-line blocks into the loop which is very bad for code placement.
if (PreMBB != &MBB &&
!LV.isLiveIn(Reg, MBB) && LV.isLiveOut(Reg, *PreMBB)) {
if (!(MLI->getLoopFor(PreMBB) == MLI->getLoopFor(&MBB) &&
if (!MLI ||
!(MLI->getLoopFor(PreMBB) == MLI->getLoopFor(&MBB) &&
MLI->isLoopHeader(&MBB)))
Changed |= PreMBB->SplitCriticalEdge(&MBB, this) != 0;
}

3
lib/CodeGen/PHIElimination.h
View File

@ -24,7 +24,6 @@ namespace llvm {
/// Lower PHI instructions to copies.
class PHIElimination : public MachineFunctionPass {
MachineRegisterInfo *MRI; // Machine register information
MachineLoopInfo *MLI;
public:
static char ID; // Pass identification, replacement for typeid
@ -52,7 +51,7 @@ namespace llvm {
/// Split critical edges where necessary for good coalescer performance.
bool SplitPHIEdges(MachineFunction &MF, MachineBasicBlock &MBB,
LiveVariables &LV);
LiveVariables &LV, MachineLoopInfo *MLI);
/// SplitCriticalEdge - Split a critical edge from A to B by
/// inserting a new MBB. Update branches in A and PHI instructions